Agronomist's top tips to beat the drought

Will Freebairn with children Audrey and Shaun check tropical grass Premier digit responding to light early January rain falling on our property in 2019. Tropical grass played a vital role in our drought management.
Will Freebairn with children Audrey and Shaun check tropical grass Premier digit responding to light early January rain falling on our property in 2019. Tropical grass played a vital role in our drought management.

While lots of strategies are important for drought management, in our case nothing was more critical than the approximately 50 per cent of the property established to tropical grasses and 20 per cent sown late summer/early autumn to winter fodder crops.

Between mid-September until the end of May (8.5 months) each year, tropical grasses have been able to respond quickly to any rain event more than about 5mm and provide valuable feed.

Growth response dried off reasonably soon after low rain events, but not for more than a month when the few well-spaced rains occurred over the drought (March 2017, October 2017, December 2017, March 2018, March 2019). And because of good soil fertility, dried-off feed remained good quality as there was little follow-up rain to adversely downgrade it.

We estimate tropical grass provided up to 40kg/ha drymatter per mm of rain. That water use efficiency would not have been possible on heavy soil, but is possible on lighter country in drought years.

Winter dual-purpose fodder crops, with every possible drop of fallow rainfall conserved, has been the basis of feeding livestock over the period tropical grasses are dormant. Ensuring these crops are sown more or less on time has been a challenge in these dry years.

Bob and Sue Freebairn's grandson and agricultural student James Anderson, checks dual purpose winter cereal in mid May 2019.

Bob and Sue Freebairn's grandson and agricultural student James Anderson, checks dual purpose winter cereal in mid May 2019.

Reasonable stubble retention, early fallow spraying after any late spring summer rain, widening the sowing window (earlier than normal) plus a contractor with sowing equipment that allows germination on a minimal rainfall event have all been important.

Some feel weeds and self-sown crop growing in the fallow are too valuable for feed to spray out. My view is grazing fallow herbage is "short-term gain for long-term pain". Especially when a dry autumn/winter early spring follows, lack of conserved fallow moisture almost guarantees fewer sowing opportunities as well as lack of stored soil moisture to keep the crop growing over the winter.

Winter forage or dual-purpose crops, can survive indefinitely on lack of follow up rain and that was well demonstrated in the last three autumn/winters. If available, lighter soils improve the probability of timely sowing.

I've also learnt from several farmers that, although a risk, sowing earlier than normal can improve timely sowing probability. For example, in our area mid-February onwards rather than early March onwards.

Previous grazing management of perennial grasses can have a big bearing on their recovery rate when it does eventually rain. If they have been periodically allowed to flower, have reasonable recovery periods, and not grazed into the ground, their ability to recover is faster.

Reasonable groundcover also helps for better water capture should a storm occur. I saw many paddocks with little or no groundcover that lost over half their rain via runoff from storms.

Another view of dual purpose winter crop this current year. Sowing on stored soil moisture has been critical.

Another view of dual purpose winter crop this current year. Sowing on stored soil moisture has been critical.

Winter legumes have not been much good for winter/spring feed for many people, including ourselves these past two years. However, because they are hard seeded varieties there has again been a good germination this autumn with the possibility of them contributing feed later on and building soil nitrogen for the grasses.

Like many farmers we could have managed this drought better in many respects. We were a bit slow to begin destocking but fortunately budgeting feed supply allowed for offloading stock at good market prices.

In our case a good agent (Galton and Co) has been critical in sound marketing. Rather than traditional supermarket weights we commonly sold to feedlots. Selling cattle lighter and earlier provided opportunities to restock and again offload successfully.

Another key aspect of drought management has been good soil fertility. Plants generally have higher water use efficiency if soil fertility is good, and feed quality is higher.

Again, changed strategies to reflect the season can be important. In 2017 and 2018 we could not see an opportunity to top-dress winter crops with nitrogen (no reliable in-crop rainfall forecast) but were able to divert it to tropical grasses ahead of better forecasts.

Next week: Research reveals way to greater soil quality, combined with greater productivity.

  • Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.